The games can be just a simple "choose your own adventure", or they can have more gameplay with it. Usually, when they do, it's an RPG mix. They usually contain nudity and sex scenes. It is a shame that the western audience is mostly fine with shooting an innocent person in the face but isn't OK with consensual sex in video games. But who cares about that when you can play these by yourself and no one has to know about it.

Visual novels can be found usually on PC, but there are console ports (these are usually strip from their erotic scenes) and even console exclusives. Not every visual novel has sex and nudity in them, and most of them take tens of hours to read/play. Even the ones with adult content in them often have routes in which the player can actually avoid seeing anything naughty. Certain games like Cartagra actually give better endings for not being a pervert!

Japan has a crap load of visual novels. Westerners have also made their own games. This is a list that doesn't make an effort to tell them apart. All recommended visual novels from all platforms are welcome. If there isn't an English translation to said game, it shall be noted.

"English" means there is an Official English port of this game for sale out there. If you enjoy these games, support the creators by buying a real copy! Many of these games have patches out there if there is no English port, so look around and see what you can find to spruce up your nice legal copy of the game.

"Adult" means that at least one path has adult content in it (nudity, sex, ect). Again, the adult content is usually avoidable if the player so chooses, but the option is there!